1. Field of the Invention
The present invention relates to multilayer capacitors, and in particular, to a multilayer capacitor which is used in a high-frequency circuit.
2. Description of the Related Art
As a decoupling capacitor that is used in a power supply circuit for an MPU (micro processing unit) in a high-frequency range on the order of several GHz, a known multilayer capacitor is disclosed in Japanese Unexamined Patent Application Publication No. H11-144996. According to this multilayer capacitor, multiple terminals are provided and adjacent terminals have opposite polarities, so that currents from positive terminals to negative terminals are short and currents flow in various paths. Furthermore, currents are caused to flow in opposite directions so that magnetic fluxes are canceled, and a reduction of an ESL (equivalent series inductance) is achieved.
However, according to the multilayer capacitor disclosed in Japanese Unexamined Patent Application Publication No. H11-144996, an ESR (equivalent series resistance) also decreases with decreasing ESL. This leads to a problem in that an attenuation phenomenon such as voltage drop and ringing is likely to occur when a resonant phenomenon occurs due to the inductance of a peripheral circuit.
Japanese Unexamined Patent Application Publication No. 2001-284170 discloses that for each internal electrode provided in a capacitor body defining a capacitance, only one lead-out portion extending to the surface of the capacitor body and electrically connected to an external terminal electrode is provided, so that the ESR of the multilayer capacitor is increased.
However, according to the structure described in Japanese Unexamined Patent Application Publication No. 2001-284170, although an ESR can be increased, an ESL increases with increasing ESR. This causes a problem of degradation of high-frequency characteristics and a decrease in the width of the frequency band, as compared with the structure described in Japanese Unexamined Patent Application Publication No. H11-144996.
In addition, in the structures described in Japanese Unexamined Patent Application Publication No. H11-144996 and Japanese Unexamined Patent Application Publication No. 2001-284170, in order to change a resonant frequency of the multilayer capacitor, it is necessary to change the material or design of the internal electrodes. Thus, it is difficult to set a resonant frequency to the high frequency side or to the low frequency side while maintaining the capacitance at substantially the same level.